Pear &#39;HW624&#39;

ABSTRACT

The invention is a new and distinct pear tree variety denominated ‘HW624’. The new pear tree is characterized by producing heavy crops of medium-to large-sized fruit, picked about 2 weeks after ‘Bartlett’. Fruits are green when harvested, turning yellow as fruits ripen, and there is a medium red blush where exposed to the sun. There were no natural fire blight infections on the seedling tree, and results from controlled inoculations indicate a high level of resistance to fire blight. The tree is also highly resistant to pear  psylla.

LATIN NAME OF THE GENUS AND SPECIES OF THE PLANT CLAIMED

Pyrus communis

VARIETY DENOMINATION

‘HW624’

BACKGROUND OF THE INVENTION

The new and distinct pear tree described and claimed herein originated from a controlled cross between ‘Harrow Sweet’ and NY10353 made in 1988 at Agriculture and Agri-Food Canada Harrow Research Station in Harrow, Ontario. Pedigree of ‘HW624’ is shown in FIG. 1.

‘HW624’ was selected as a hybrid seedling (H8806-1) in 1995 and propagated by budding on pear seedling rootstocks. Trees were planted in an evaluation orchard at the Agriculture and Agri-Food Canada Research Farm at Jordan Station in 1999. This selection was advanced and tested in regional trials in cooperation with the Western Ontario Fruit Testing Association beginning in 2000.

SUMMARY OF THE INVENTION

On the new pear tree ‘HW624’, the profile of the sides of the fruit of ‘HW624’ is straight whereas they are concave on the reference varieties Bosc (R1), Harrow Sweet (R2), AC Harrow Crisp (R3) and Bartlett (R4). The ground colour of the skin of ‘HW624’ is yellow whereas it is yellow green on ‘Bosc’, ‘Harrow Street’ and ‘Bartlett’. ‘HW624’ has a medium to large area of over colour of the skin whereas there is none on ‘Bosc’, small to medium area on ‘Harrow Street’ and very small on ‘Bartlett’. The over colour of ‘HW624’ is dark red whereas it is orange red on ‘Harrow Street’, ‘AC Harrow Crisp’ and ‘Bartlett’. ‘HW624’ has no russetting around the eye basin, on the cheeks or around the stalk attachment of the fruit whereas ‘Bosc’ has a large to very large area. The fruit stalk of ‘HW624’ is thin whereas it is medium thickness on ‘Harrow Street’ and ‘AC Harrow Crisp’ and thick on ‘Bartlett’. ‘HW624’ has weak curvature of the fruit stalk whereas the curvature is medium to strong on ‘Bosc’, medium on ‘AC Harrow Crisp’ and absent on ‘Bartlett’. The attitude of the sepals on the fruit of ‘HW624’ is preading whereas it is erect on ‘Bosc’ and ‘Harrow Street’ and converging on ‘AC Harrow Crisp’ and ‘Bartlett’. ‘HW624’ is resistant to moderately resistant to fireblight (Erwinia amylovora) whereas ‘Bosc’ is moderately susceptible and ‘Bartlett’ is susceptible. ‘HW624’ is resistant to moderately resistant to pear psylla (Cacopsylla pyricola Foerst) whereas the reference varieties are susceptible.

The following are major distinguishing characteristics. ‘HW624’ is a mid-late season pear cultivar for the fresh market. ‘HW624’ produces heavy crops of medium-to large-sized fruit, picked about 2 weeks after ‘Bartlett’. Fruits are green when harvested, turning yellow as fruits ripen, and there is a medium red blush where exposed to the sun. The tree has consistently produced heavy crops, with no evidence of biennial bearing. There were no natural fire blight infections on the seedling tree, and results from controlled inoculations indicate a high level of resistance to fire blight. The tree is also highly resistant to pear psylla (Cacopsylla pyricola Foerst). In years when orchard populations of psylla have been high, trees of ‘HW624’ have had no noticeable presence of this insect pest. ‘HW624’ is not graft-compatible with quince rootstocks. The characteristics most useful in distinguishing ‘HW624’ are fruit characteristics and resistance to fire blight and resistance to pear psylla.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying photographic illustration illustrates in full color ‘HW624’. The colors are as nearly true as reasonably possible in color representation of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description below, which accurately describes the colors of the new pear tree.

FIG. 1 shows pedigree of ‘HW624’.

FIG. 2 shows five examples of the fruit of ‘HW624’ compared to the fruit of Bosc (R1), Harrow Sweet (R2), AC Harrow Crisp (R3) and Bartlett (R4).

DETAILED BOTANICAL DESCRIPTION OF THE INVENTION

The ‘HW624’ variety is uniform and stable. Asexual propagation maintains uniformity and stability. No off-types, variants or mutations have been found to date. Virus-tested ‘HW624’ is maintained at the Canadian Food Inspection Agency, Centre for Plant Health in North Saanich, British Columbia.

The R.H.S. Colour Chart of The Royal Horticultural Society has been used for colour identification of fruit and shoot. The description is based on observation of four trees grafted on seedling rootstock originally established during the 1999 growing season. Comparisons were made with Bosc (R1), Harrow Sweet (R2), AC Harrow Crisp (R3) and Bartlett (R4). Four trees of each variety grafted on Bartlett open pollinated seedling rootstock were spaced about 3 metres apart with about 4.5 metres between rows and were observed during the 2009-2010 growing seasons at the Jordan Road Farm of Agriculture and Agri-Food Canada Research Centre in Jordan Station, Ontario. Fire blight evaluations and observations were conducted in 1988-2000 at the Agriculture and Agri-Food Canada Harrow Research Centre.

‘HW624’ R1 R2 R3 R4 Tree: Vigor medium very medium strong medium to strong strong to strong Branching strong medium strong medium medium to strong to strong Habit spreading spreading spreading spreading spreading to drooping Shoot-One-year-old: Growth wavy wavy wavy straight straight to to Length of wavy wavy internode Mean 3.42 4.28 3.02 3.26 3.55 Std. deviation 0.37 0.67 0.48 0.58 0.46 Predominant brown brown orange medium orange colour on purple purple brown brown brown sunny side Number of many many medium medium medium lenticels to many to many to many Shape of apex acute acute acute acute acute of vegetative bud Position of slightly slightly slightly slightly adpressed vegetative held out held out held out held out bud in relation to to shoot markedly held out Size of bud medium small to small to medium small to support medium medium medium Shoot-Young: Anthocyanin very strong to medium medium medium colouration of strong very to strong growing tip strong (during rapid growth) Intensity of weak to weak to weak to weak to medium pubescence medium medium medium medium (upper third) Leaf-Blade: Attitude in outwards down- outwards outwards outwards relation to wards shoot Length (cm) Mean 6.5 7.1 7.1 6.3 6.5 Std. deviation 1.0 1.3 1.2 0.8 0.7 Width (cm) Mean 4.3 4.3 3.8 3.8 3.9 Std. deviation 0.7 1.0 0.8 0.7 0.6 Length/Width small to medium medium medium medium ratio medium to large Shape of base right- obtuse right- right- right- angled angled angled angled to to obtuse obtuse Shape of apex obtuse right- right- right- right- (excluding angled angled angled angled pointed tip) to obtuse Length of short short short short to short pointed tip very short Incisions of bluntly crenate bluntly bluntly bluntly margins serrate serrate serrate serrate (upper half) Depth of inci- shallow shallow shallow shallow shallow sions of margin Curvature of very weak to weak weak very longitudinal weak medium weak axis Leaf-Petiole: Length (cm) Mean 2.7 2.2 2.4 2.1 2.0 Std. deviation 0.6 1.0 0.7 0.7 0.8 Presence of present Absent or present present present stipules weakly Distance of medium medium short to short to short stipules from to long medium medium basal attach- ment of petiole Flower: Time of be- early medium early to medium medium ginning of to late medium to late flowering Location of mainly mainly mainly mainly mainly flower bud on on spurs on spurs on spurs on spurs on spurs shoot Length of - flower bud (cm) Mean 5.4 5.9 5.5 6.3 4.1 Std. deviation 0.7 0.5 0.6 0.4 0.3 Sepal length (cm) Mean 5.9 8.3 6.7 7.9 7.0 Std. deviation 0.6 0.7 0.7 1.1 1.2 Attitude of recurved recurved recurved recurved spreading sepals in rela- to tion to corolla recurved Arrangement not not touching touching touching of petals touching touching to to to over- over- touching lapping lapping Position of same same above same same stigma in level level level level relation to stamens Size of petal small to medium medium small to medium medium medium Shape of circular ovate circular circular circular petal (exclud- to broad ing the claw) ovate Shape of base cuneate cuneate rounded rounded Rounded of petal (ex- to cluding the rounded claw) Length of short medium medium very short short claw of petal Fruit: Length (cm) Mean 8.7 10.2 9.1 9.1 9.0 Std. deviation 1.0 0.9 0.9 0.8 0.9 Maximum diameter (cm) Mean 6.9 7.0 6.6 6.8 6.8 Std. deviation 0.6 0.5 0.6 0.6 0.6 Length/Diam- small to medium medium medium small to eter ratio medium to large medium Position of slightly slightly slightly slightly in maximum towards towards towards towards middle diameter calyx calyx to calyx calyx clearly towards calyx Size large large medium large medium to large Symmetry (in slightly slightly slightly slightly sym- longitudinal asym- asym- asym- asym- metric section) metric metric to metric metric to strongly slightly asym- asym- metric metric Profile of sides straight concave concave concave concave Ground colour yellow yellow yellow yellow yellow of skin green green green Relative area medium absent small to medium between of over colour to large or very medium very small small and small Hue of over dark red orange orange orange colour red red red Relative area absent large to absent absent absent of russet or very very or very or very or very around eye small large small small small basin Relative area absent large to absent absent absent of russet on or very very or very or very or very cheeks small large small small small Relative area absent large to absent small very of russet or very very or very small around stalk small large small to small attachment Length of stalk (mm) Mean 3.2 5.0 3.4 3.7 2.8 Std. deviation 0.7 0.7 0.6 0.9 0.6 Thickness of thin thin to medium medium thick stalk medium Curvature of weak medium weak to medium absent stalk to strong medium or very weak Attitude of oblique oblique oblique straight straight stalk in rela- to to tion to axis oblique oblique of fruit Depth of stalk medium absent shallow medium medium cavity to deep or very shallow Attitude of spreading erect erect con- con- sepals (at verging verging harvest) Eye basin (at present present present present present harvest) Depth of eye medium shallow shallow shallow deep basin (at to deep to harvest) medium Width of eye medium narrow medium medium narrow basin (at to to broad harvest) medium Relief of area slightly slightly slightly smooth em- around eye ribbed ribbed ribbed bossed (at harvest) Texture of very very very very very flesh fine fine very very very fine fine fine Firmness medium medium soft to medium medium of flesh to firm medium to firm Juiciness medium juicy juicy to medium juicy of flesh to juicy very to juicy juicy Seed shape ovate ovate elliptic elliptic ovate Time of late very very medium medium maturity for late late to late consumption Disease/Pest Reactions: Fire blight resistant moder- resistant resistant suscep- (Elwininia to moder- ately sus- to moder- to moder- tible amylovora) ately ceptible ately ately resistant resistant resistant Pear psylla resistant suscep- suscep- suscep- suscep- (Cacopsylla to moder- tible tible tible tible pyricola) ately resistant

The ‘HW624’ variety has not been observed under all possible environmental conditions to date. Accordingly, it is possible that the phenotypic expression may vary somewhat with changes in light intensity and duration, cultural practices, and other environmental conditions. 

What is claimed:
 1. A new and distinct variety of pear tree substantially as herein illustrated and described. 